A wheel loader is provided with a steering wheel for performing steering operation during running on a public road or during high-speed running at a working site. Moreover, the wheel loader is provided with a lever such as a joy stick so that efficient steering operation can be performed with a simple operation at a working site where short-distance running and steering operation are performed repeatedly.
PTD 1 discloses a steering loader which enables steering operation by both rotating operation with use of a steering wheel and lever operation with use of a lever. According to PTD 1, since there is a case where steering operation is performed unintentionally when a driver touches a lever by mistake during rotating operation with use of a steering wheel, there has been proposed a method of allowing a steering wheel priority valve to operate so as to prioritize the operation with use of the steering wheel.
On the other hand, conventionally, a switch for enabling (validating) lever operation is provided to prevent misoperation of the lever operation. As a configuration of the switch, a configuration of providing a plurality of switch rather than a single switch has been employed. For a configuration of an electric circuit, a configuration of connecting a plurality of switches together in series and performing determination of enabling lever operation when all the plurality of switches are turned on (validated) has been employed.